The mammalian gene structure is based on coding DNA-sequences (exons) and intervening sequences (introns). Disturbances or changes (mutations) in the coding sequences result in abnormal gene products and thus malfunction and disease. Today, more than 4500 diseases are known which are due to defects in single genes. Such defects may be stable mutations, i.e. they always occur in specific, predictable positions, but may also be unstable genetic events occurring at one or more of a number of different unpredictable locations in the gene. In many cases the cause of a specific genetic disease may be stable or unstable events in any one of a number of exons. Detailed genetic information on an individual will tell about the susceptibility for disease, confirm inherited disorders, confirm disease status and serve as a guidance for more efficient treatment.
In the case of stable and thereby predictable mutations, methods permitting the determination of a specific polynucleotide sequence may be used, whereas the detection of unstable genetic events will require a DNA (or RNA) sequencing operation on the exon or exons in question. It is readily understood that with current methods, the determination of genetic diseases which may be due to one of several possible stable and unstable mutations will be laborious and time-consuming, requiring inter alia a great number of pipetting operations. The reproducibility will therefore be highly dependent on the skill of the operator. Besides, only a few commercial tests are available today for such genetic diseases, which tests, apart from being relatively complicated to perform, have a rather low accuracy.
Co-pending Swedish patent application 9203320-8 discloses a method of performing molecular-genetic reactions using a patrix-matrix type system, wherein the matrix part usually is a microtiter plate and the patrix part is a plate having a plurality of protrusions or extensions, each matching a respective well of the microtiter plate. The extensions are used as solid phase elements, each capable of binding a specific nucleic acid sequence from a solution and then keep it immobilized thereto for further processing or reaction by inserting the assembly of extensions into further microtiter wells. Such a system will permit a plurality of reactions to be performed simultaneously with reduced risk of contamination between reactions. While the use of the system for diagnostics tests is described in general, there is only a specific disclosure of the determination of stable mutations.